Design and Analysis of a 3-DOF Planar Flexure-based Parallel Mechanism with Large Motion Range

This paper presents a novel 3-degree-of-freedom (DOF) planar compliant Parallel Mechanism (PCPM). This PCPM is constituted of three identical beam-based flexible chains which are PPR kinematic chains with two mutually perpendicular prismatic (P) joints and one revolute (R) joint. Blade-flexures elements are utilized with its characteristic of distributed compliance to realize a large and linear $\mathbf{XY}\boldsymbol{\theta}_{\mathbf{z}}$ travel motion about ±3mm×±3mm×±3°. Based on the compliant parallel 4-bar mechanism, two kinds of optimized guiding mechanisms with high cross-axis stiffness and one precise rotary pivot are proposed. Matrix method is implemented to establish the quantitative compliance models of each joint and then for the whole compliant mechanism by coordinate transformation. Finite element analysis is carried out to validate both the static and dynamic performance of the 3-DOF stage. The results suggest the proposed PCPM can realize a large motion, deliver small cross-axis effects and possess a high bandwidth over 45Hz.